Dude, half the time I'm reading about young, submissive!Harry I'm thinking 'omg how is everyone allowing this to go on?' That's why when I read D/s (which is rare) I read sub!Snape. I've had a lot of people tell me that doesn't make sense, but I think it does. My reasoning: Severus is a very strong, very intelligent older wizard. Harry is his lesser in arguably every way. So Severus submitting almost levels the playing field.
Or something like that. Make sense? When Harry's the sub it's like omg someone rescue Harry!
And as for bottom!Snape, there are a few great authors who really explore Severus emotional landscape. Calligraphy was one of them. Emily Waters. Meri is good about showing Severus as a sexual being.
I think it's in "The Same Coin" where Harry is flabbergasted that Severus likes to bottom, and Severus just looks at him, shrugs and says 'it feels good.'
I think that's what bottom!Snape can be. Not for me of course because omg angst angst ANGST. But for some people. : )
And I think a well-done crying man scene is just about the best thing. It has to be done with finesse, which is exactly what you've done.